Deficiency of peripheral CLA Tregs and clinical relevance in Behcet's syndrome.

Background: Autoimmune responses have been suggested to involvement in patients with Behcet's syndrome (BS). There has been growing attention towards the roles of cutaneous lymphocyte antigen (CLA) regular T cells (Tregs) in autoimmune diseases. The role of CLA Tregs in BS is still uncertain. This study aims to clarify the impact of CLA Tregs on BS.

Methods: We collected peripheral blood from a total of 107 patients with BS and 114 healthy controls (HCs). The number of CLA Tregs, natural killer (NK) cells, B cells, and several subtypes of CD4 T cells were detected using flow cytometry and compared between patients and HCs.

Results: The absolute number and proportion of CLA Tregs among CD4 T lymphocytes and CD4 Tregs were lower in patients with BS than in HCs. CLA Tregs were positively related with NK cells (r = 0.500, P < 0.001) and B cells (r = 0.470, P < 0.001) and negatively related with effector T cells (r=-0.402, P < 0.001) in patients with BS. Patients with BS and arterial aneurysms had CLA Treg cell deficiency. A decreased proportion of CLA Tregs was associated with arterial aneurysms in patients with BS. The proportion of CLA Tregs in patients with BS increased with corticosteroids and immunosuppressants.

Conclusion: CLA Tregs decrease in association with arterial aneurysm in patients with BS. CLA Tregs may be a predictor of response to BS treatment.